Antibacterial personal care compositions are known in the art. Especially useful are antibacterial cleansing compositions, which typically are used to cleanse the skin and to destroy bacteria and other microorganisms present on the skin, especially the hands, arms, and face of the user.
Antibacterial compositions are used, for example, in the health care industry, food service industry, meat processing industry, and in the private sector by individual consumers. The wide-spread use of antibacterial compositions indicates the importance consumers place on controlling bacteria and other microorganism populations on skin. It is important, however, that antibacterial compositions provide a substantial and broad spectrum reduction in microorganism populations quickly and without problems associated with toxicity and skin irritation.
In particular, antibacterial cleansing compositions typically contain an active antibacterial agent, a surfactant, and various other ingredients, for example, dyes, fragrances, pH adjusters, thickeners, and the like, in an aqueous carrier. Several different classes of antibacterial agents have been used in antibacterial cleansing compositions. Examples of antibacterial agents include a bisguanidine (e.g., chlorhexidine digluconate), diphenyl compounds, benzyl alcohols, trihalocarbanilides, quaternary ammonium compounds, ethoxylated phenols, and phenolic compounds, such as halo-substituted phenolic compounds, like PCMX (i.e., p-chloro-m-xylenol) and triclosan (i.e., 2,4,4′-tri-chloro-2′hydroxy-diphenylether). Present-day antimicrobial compositions based on such antibacterial agents exhibit a wide range of antibacterial activity, ranging from low to high, depending on the microorganism to be controlled and the particular antibacterial composition.
Most commercial antibacterial compositions, however, generally offer a low to moderate antibacterial activity. Antibacterial activity is assessed against a broad spectrum of microorganisms, including both Gram positive and Gram negative microorganisms. The log reduction, or alternatively the percent reduction, in bacterial populations provided by the antibacterial composition correlates to antibacterial activity. A log reduction of 3-5 is most preferred, a 1-3 reduction is preferred, whereas a log reduction of less than 1 is least preferred, for a particular contact time, generally ranging from 15 seconds to 5 minutes. Thus, a highly preferred antibacterial composition exhibits a 3-5 log reduction against a broad spectrum of micro-organisms in a short contact time. Prior disclosures illustrate attempts to provide such antibacterial compositions, which, to date, do not provide the rapid, broad range control of microorganisms desired by consumers.
It should be noted that high log reductions have been achieved at pH values of 4 and 9, but such log reductions are attributed at least in part to these relatively extreme pH values. Compositions having such pH values can irritate the skin and other surfaces, and, therefore, typically are avoided. It has been difficult to impossible to achieve a high log reduction using an antibacterial composition having a neutral pH of about 5 to about 8, and especially about 6 to about 8.
However, highly efficacious antibacterial compositions suffer in comparison to regular (i.e., nonantibacterial) personal care compositions with respect to acceptable consumer properties, especially foam characteristics and imparting skin care properties, such as skin conditioning. It also is difficult to provide phase stable, highly efficacious antibacterial compositions having consumer-acceptable esthetics. Further, present-day antibacterial personal care compositions do not provide an effective antibacterial activity, especially against pathogenic Gram negative bacteria. Thus, a need exists for phase stable, efficacious antibacterial personal care compositions containing skin care ingredients, and that further are consumer acceptable.
An example of patents and published applications disclosing compositions comprising triclosan, surfactants, solvents, chelating agents, thickeners, buffering agents, and water is WO 98/01110. WO 98/01110 is directed to reducing skin irritation by employing a reduced amount of surfactant.
Fendler et al. U.S. Pat. No. 5,635,462 discloses compositions comprising PCMX and selected surfactants. The compositions disclosed therein are devoid of anionic surfactants and nonionic surfactants.
WO 97/46218 and WO 96/06152 disclose compositions based on triclosan, organic acids or salts, hydrotropes, and hydric solvents.
EP 0 505 935 discloses compositions containing PCMX in combination with nonionic and anionic surfactants, particularly nonionic block copolymer surfactants.
WO 95/32705 discloses a mild surfactant combination that can be combined with antibacterial compounds, like triclosan.
WO 95/09605 discloses antibacterial compositions containing anionic surfactants and alkyl-polyglycoside surfactants.
WO 98/55096 discloses antimicrobial wipes having a porous sheet impregnated with an antibacterial composition containing an active antimicrobial agent, an anionic surfactant, an acid, and water, wherein the composition has a pH of about 3.0 to about 6.0.
Glenn, Jr. et al. U.S. Pat. No. 5,885,948 discloses a stress stable, lathering skin cleansing composition containing about one to 30 parts lipid skin moisturizing agents.
Beerse et al. U.S. Pat. Nos. 5,968,539; 6,106,851; and 6,113,933 disclose antibacterial compositions having a pH of about 3 to about 6. The compositions contain an antibacterial agent, an anionic surfactant, and a proton donor.
N. A. Allawala et al., J. Amer. Pharm. Assoc.—Sci. Ed., Vol. XLII, no. 5, pp. 267-275, (1953) discusses the antibacterial activity of active antibacterial agents in combination with surfactants.
A. G. Mitchell, J. Pharm. Pharmacol., Vol. 16, pp. 533-537, (1964) discloses compositions containing PCMX and a nonionic surfactant that exhibit antibacterial activity. The compositions disclosed in the Mitchell publication exhibit antibacterial activity in at least 47 minutes contact time, thus the compositions are not highly effective.
Prior disclosures have not addressed the issue of providing an antibacterial composition that (a) affords an effective, fast, and broad spectrum control of bacteria at a neutral pH of about 5 to about 8, and especially at about 6 to about 8, (b) is phase stable, (c) exhibits excellent esthetic properties, such as a stable, copious foam generation, and (d) imparts skin care properties to cleansed skin. In addition to the above, prior disclosures also have not addressed providing a composition of sufficiently low viscosity for use with a self-foaming pump.
An efficacious antibacterial composition has been difficult to achieve because of the properties of the antibacterial agents and the effects of a surfactant, a hydrotrope, and a hydric solvent on an antibacterial agent. One such efficacious antibacterial composition is discussed in Taylor et al. U.S. Pat. No. 6,107,261, incorporated herein by reference. This patent discloses a highly efficacious antibacterial composition against Gram negative and Gram positive bacteria, and containing a high percent (at least 25%) saturation of a phenolic antibacterial agent. The positive effects of a higher percent of saturation of antibacterial agent is fully discussed in U.S. Pat. No. 6,107,261.
A need now exists for an antibacterial composition that is highly efficacious against a broad spectrum of Gram positive and Gram negative bacteria in a short time period, wherein the antibacterial activity is attributed primarily, or solely, to the presence of the active antibacterial agent in the composition, and has consumer-acceptable esthetic properties with respect to phase stability, feel, foam generation and stability, and imparting skin care properties. The present invention is directed to such efficacious and esthetically pleasing antibacterial compositions.
The development of such compositions is difficult because of factors such as a) the need for a high antimicrobial efficacy even in the presence of esthetic enhancing and skin care additives, b) the need to maintain a relatively high % saturation of the antibacterial agent, and c) the difficulty in formulating a high-foaming composition in the presence of significant amounts of a hydrotrope and hydric solvent. Unlike present-day commercial compositions and compositions disclosed in the prior art, the variety, type, and amounts of esthetic enhancing and skin care additives that can be incorporated in the present compositions are varied and unexpected, and a high percent saturation of antibacterial agent can be maintained.
In addition, antibacterial composition viscosity also is critical for particular applications. For example, a preferred method of using the composition is with a self-foaming pump. If the viscosity of the composition is too high (e.g., greater than about 50 centipoise), the composition cannot be pumped through a preferred foaming device. Finally, foam generation and stability also are important for consumer acceptability. Compositions of the present invention exhibit excellent viscosity, enhanced foam volume, creaminess, and slip during human use tests. This is especially important for application of the antibacterial composition to dry hands through a foaming pump, followed by about 30 seconds lathering, and completed by rinsing with water. This type of application provides the highest antibacterial effect.